The danger of exposure to chemical or biological agents can be severe. Whether a result of unintended release by way of, e.g., an accident, or a result of intentional delivery, it is desirable to quickly and accurately identify (1) the type of agent that has been released and (2) the precise area of contamination. Early and accurate detection of such dangerous substances can be a significant factor in reducing potential casualties and limiting further spreading of the agent by, e.g., wind, human or animal contact, among other transmission mechanisms.
In recent years, there has been an increased interest in developing and deploying sensor technologies to quickly identify unknown substances, contaminants, and agents, even at very low concentrations. Some of these technologies are designed to measure surface-deposited contamination using vehicles and associated test equipment to retrieve a physical sample of the contaminant and then employ extremely cumbersome and time-consuming processes based on a mechanical sampling wheel system to test for agents.
In view of the complexity of such approaches, newer, safer and more reliable technologies have emerged. One such technology is referred to, generally, as “standoff surface detection,” and refers to a category of technologies that permit detection of substances without actually having to physically come in contact with the substance or agent of concern. The goal of these detection systems is to enable the capability to detect, identify, locate, quantify, warn, and report chemical or biological threats and thereby give military forces or civilian personnel sufficient early warning to avoid (further) contamination.
An example of a standoff surface detection system is a technology known as Laser Interrogation of Surface Agents (LISA®) that has been developed by ITT Corp. (White Plains, N.Y.). In one implementation, LISA® uses a laser and associated components attached to a reconnaissance vehicle such as a truck or High Mobility Multipurpose Wheeled Vehicle (HMMWV) that searches for chemical agents on the ground (or any surface) using a technique known as Raman Scattering (or Raman Effect, or Raman spectroscopy), which is an optical property that can be exploited to identify chemical and biological agents. LISA® employs several components including an intensified charge coupled device (ICCD) for capturing Raman spectra. LISA® also provides the ability to create or generate a position detection map with inputs from, e.g., a global positioning satellite (GPS) system, with chemical agent contours that build up as detection is taking place.
Standoff biological agent detection is significantly more difficult than chemical detection. Specifically, it is often difficult to discriminate and measure biological agents from naturally occurring background materials. Moreover, real-time detection and measurement of biological agents in the environment can be daunting because of the number of potential agents to be identified, the complex nature of the agents themselves, the countless number of similar microorganisms that are a constant presence in the environment, and the minute quantities of pathogen that can initiate harmful reactions. Potential biological agents can also disguise themselves in benign entities.
In light of these and other obstacles and in furtherance of more accurate contaminant or, more generally, unknown substance, detection and identification capabilities, there is still a need for improvements in stand-off detection systems, as well as other systems that might rely on sophisticated spectral analysis, such as Raman spectroscopy, or electronic imaging.